Incandescent lamp stem



May 16, 1933. J. A; DONOHOE INCANDESCENT LAMP v STEM Filed ma 18, 1929 (LAJDONOHQE BY 7 9 v ATTORNY' Patented May 16, 1933 raga JAMES A. DONOEOE, OF TRENTON, NEW JERSEY, ASSIGNOR. TO WESTINGHOUSE ill-1MP COMPANY, A CORPORATION OF. PENNSYLVANIA INCAKDESCENT LAMP STEM Y Application filed may 18, 1929. Serial ,No. 364,116.

This invention relates to the manufacture of stems for incandescent electric lamps or similar devices. The manufacture of incandescent electric lamps includes an envelope or bulb into which is sealed what is termed a lamp mount. The mount usually consists of a flare tube, an exhaust tube, an arbor, as well as a pair of leading-in conductors all of which are consolidated in what is termed a press to constitute a unitary structure. This structure is termed a stem and is ready to havedisposed in axlal alignment with the longi: tudinal axis of a glass flare tube. A pair of leading-in wires are also positioned within the flare tube and heat is applied adjacent to the unflared end of the flare tube at which time the said end is compressed, forming what is termed a press so as to fuse and consolidate the flare tube and the internally supported tube together, as well as to seal-in the leading-in wires at the press portion.

Means are provided for directing a jet of air under pressure into one end of the centrally supported" tube, while the portion termed the press is still plastic so that the wall of the flare tube is puncturedand anaperture is provided for communication between the internally supported tube and the interior of a lamp bulb for exhaust purposes after the stem has been sealed to the bulb.

When constructing a lamp stem as above described'the portion of the central tubular memberextending from within the flare tube is utilized as the exhaust. tube and the end of the tubular member projecting outwardly from the press is utilized as an arbor to restem by supporting a length of glass tubing oeive support wires. For the purpose of obtaining material to receive the ends of support wires, which carry the filament, an end of the arbor is rendered plastic and compressed into What is termed a button at which time means are provided for leaving the top of the button open so as to afiord communication to the interior of the hollow arbor. This, is necessary so that when the bulb is exhausted all gases will be drawn out of m the arbor as well as the bulb.

It has been found that lamp stems made in accordance With the above practice present certain disadvantages. I Difliculty has been experienced in providing the aperture in the button since in forming this aperture it is necessary to employ a pointed tool which has a tendency to adhere to the glass throwing the button out qt proper position with respect to the arbor and since any deformation with respect to the position of the button results in difiiculties in, connection with the insertion of the support wires, stems made in the above manner presented disadvantages from a manufacturing standpoint. The support wire inserting mechanism op crates to insert the support wires by movement through definite paths and when the button is not properly positioned the support wires will be inserted an insufficient depth or 30 not inserted at all, with the result that the automatic mechanism which must operate at relatively high speed is attended by an appreciable amount of loss through defectivestems.

It is an object of the present invention to 5 provide a lamp stem having a hollow arbor and a uniformly formed and accurately positioned button thereon.

Another object of the invention is to provide a lamp stem having a uniformly positioned button and an aperturefor exhausting the arbor.

Another object of the invention is to pro-- vide a method of producing a lamp stem having a hollow arbor and a button for receiving support wires and for closing an end of said arbor. 7

Other objects and advantages ofthe IlIlVBIl. tion will be more fully understood with reference to the following description together 10o with the accompanying drawing, in which Fig. 1 shows a lamp stem having a hollow arbor ready to be provided with an aperture.

' annealing fire directed upon an aperture in the arbor.

Fig. 5 is a View of astem with means for formmg a button at the end of an arbor, and

Fig. 6 shows an arbor constructed in accordance with the present invention and complete to support a lamp filament.

In practicing the present invention stems may be provided comprising an exhaust tube 10, a flare tube 11 and an arbor 12. The arbor and flare tube which are initially of a continu ous tubular member are united to the flare tube at 13 in what is termed a press which results from pressure being applied to heated portlons of the positioned glass parts. Lead wires or conductors 14 and 15 extend through the press and are sealed therein.

A stem constructed asabove described may then be supported and heat provided by a flame 16 may be directed against a wall 17 of the arbor '12. When .the wall is heatedto the proper plasticity a nozzle '18 directs air under pressure into the arbor so as to puncture the wall thereof at the plastic portion, and an aperture 19 is provided. The perimeter of the aperture 19 may then be annealed by directing a flame 20 thereagainst.

The stem may then be properlysupported and the exposed end 21 of the arbor may be .heated by a flame 22 untilplastic, at which time apressure member 23 may be moved to engage the plastic end and form a button wires 25 which may be applied by mechanism- '26,-compr1smg the usual insertingv ram of a- 24, at the same time, closing the end o f'the arbor and producing a solid symmetrically positioned mass for the insertion of support support wire inserting machine.- After the support wlres are inserted they may be bent upwardly as shown in Fi 6 and a filament 2 may be mounted therem and the ends of the filament suitably secured to the lead wires 14 and 15. i

A lamp stem constructed in accordance with the present method is provided with a hollow arbor having an end closure in the form of a button which is so positioned as to he in a plane transverse to the longitudinal axis of the'arbor. Itis therefore possible. to provide a glass mass into which the support wires may be securely and deeply embedded, and furthermore by reason of the provision of an aperture in the side wall of the arbor a larger opening is possible than has heretofore been obtainable and a more complete exhaustion of the interior of the arbor is attained.

It will be understood that in the manufacture of an article such as an incandescent electric lamp it is extremely important that the various lamp parts be made with the proper degree of uniformity so as to meet the method and at the same time the required uniformity to meet practical manufacturing demands is attaine Although a preferred embodiment of the invention is shown and described herein it is I to be understood that modifications may be made therein Without departing from the spirit and scope of the invention as set forth in the appended claims.

What is. claimed is: 1. The method of manufacturinga lamp stem having a hollow arbor which comprises applying heat to the wall of the arbor to render plastic a portion thereof, puncturing the wall at the plastic portion, heating the exposed end of said arbor, and compressing the heated portion to enlarge the same and close the said end.

' 2. The method of manufacturing a lamp stem having a hollow arbor closed at one. end by the press of the stem which comprises applying heat to aportion of the wall of said arbor, directing air under pressure into the open end of the arbor to puncture the recting fluid into the open end of the arbor to puncture thewall at the heated portion, annealing the perimeter of the puncture and heating and compressing to close the open end of the arbor by an enlargement.

4-. The method of manufacturing a lamp' stem having a hollow arbor which comprises applying heat to the wall of the arbor; to render plastic a portion'thereof, puncturing the wall at the plastic portion, heating the exposed end of said arbor, compressing the said portion to enlarge the same and close the said 'end and insertingsupport wires in the said enlarged portion.

In .testimony whereof, I have hereunto subscribed my name this 14th day of May,

I JAMES A, DQNOHOE. 

